Many structures have been devised to prevent combustible gases from preigniting before reaching the nozzle of the head of a burner. Some of these devices have been more successful than others. The more effective such devices have been relatively complex and expensive but have generally achieved the desired result.
Often the incoming flammable gas to a burner head is a relatively lean mixture. Under most circumstances external air further dilutes the gas being emitted from the burner head, that is, the gas in the pre-combustion zone. Sometimes this dilution reduces the concentration of combustible elements of the gas below that which can maintain a flame, and the burner will fail to remain lighted. Various structures have been proposed to solve this problem.
Another requirement for burners, at least under some circumstances, is that it include, or function as, a flame arrester. Flame arrestors are also well known and generally effective, but frequently they are also relatively complex and costly.
What has not been generally available has been a very simple, inexpensive and effective burner head which not only prevents autoignition, but also acts as a flame arrester and prevents the adverse effects of dilution air.